Conventionally, as an apparatus for evaluating an activity and life of a solid catalyst, a selectivity of a product and a quality of a product on a laboratory scale, an apparatus using an isothermal tubular reactor is frequently used.
As disadvantages of this tubular reactor, the following points have been indicated.
(1) Since a flow rate is lower than that of a large scale tubular reactor (hereinafter, referred to as an actual apparatus) used for an commercial purpose, the apparatus is effected by a mass transport limitation, so that there is a fear that the obtained evaluation results are different from that of the actual apparatus.
(2) When a diameter of the tube is too small, the apparatus is significantly effected by a maldistribution due to the wall, and when a length of a packing layer is too short, the apparatus is significantly effected by a back mixing.
(3) In a system of great endothermic reaction or great exothermic reaction, not only it is hard to maintain an isothermal condition, but also a difference is generated between a surface temperature of the catalyst (an actual reaction temperature) and a temperature of a fluid, so that it is hard to recognize the actual reaction temperature.
(4) Since the structure is made such that the fluid is successively reacted from an inlet to an outlet of the catalyst layer, a concentration of a material to be reacted, a reaction rate and a concentration of a poisoning material collected on the catalyst are largely different when seen in a finely divided section. Accordingly, it is hard to accurately obtain a reaction rate and a deterioration characteristic of the catalyst.
Therefore, hitherto, it has been a common sense that as well as the scale of the experimental apparatus has been gradually enlarged, the research and development has been proceeded while recognizing the influences of the above items (1) to (4).
Further, there has been suggested various kinds of evaluation apparatuses using a reactor each of which is designed for the purpose of solving the disadvantages of the above items (1) to (4) on a laboratory scale. The apparatus will be described below while indicating the source thereof.
(1) Berty Reactor
1) Berty, J. M. et al.; 64th National Meeting A. I. Ch. E Preprint 42E (1969)
There are shown evaluation results (hydrogenation of ethylene) in the case that a fluid in a 5 inch type reactor (named at the later time) is a gas phase and a chart for calculating a flow rate of a gas passing through a catalyst layer.
A summary of applied examples published later is shown in Table 1 together with cited references.
TABLE 1 ______________________________________ Purpose of Condition of Reaction used research reaction References ______________________________________ Hydrogenation Recognition of 100.degree. C. 2), 4) of ethylene performance of 10-20 atm reactors Synthesis of Consideration 232.degree. C. 5) methanol of runaway 52 atm condition Synthesis of Consideration 255.degree. C. 8) methanol of catalyst 16 atm species and catalysis Dehydrogenation Consideration 270-380.degree. C. 6) of of reaction 1-2 atm cyclohexanol kinematics Aromatization Recognition of 370-590.degree. C. 7) of n-heptane deteriorating behavior CO oxidation Consideration 160-200.degree. C. 9) of kinematic model Verification of optimum control model Methanation of Consideration 237-337.degree. C. 10) CO of 69 atm deteriorating rate equation Sublimation of Recognition of 23.degree. C. 11) naphthalene performance of 0.87 atm reactor Oxidation of Consideration 363-363.degree. C. 12) SO.sub.2 of kinematic 2.5-10 atm equation ______________________________________ References 2) Berty J. M. et. al., AlChE 64th National Meeting 42E (1969) 4) Berty J. M. , Chem. Eng. Prog., 70(5), 78 (1974) 5) Berty J. M. et. al., AlChE J., 28(6), 914 (1982) 6) Gut G. et. al., Chem. Eng. Sci., 37(2), 319 (1982) 7) Mahoney J. A., J Catal., 32, 247 (1974) 8) Kelly K. P. et. al., J Catal., 101, 396 (1986) 9) Broucek R. et. al., Chem. Eng. Sci., 41(11), 2901 (1986) 10) Bowman R. M. et. al., Appli. Catalysis, 7, 179 (1983) 11) Caldwell L., Appli. Catalysis. 8, 199 (1983) 12) Doering F. J., Chem. Eng. Sci., 43(2) 221 (1988)
2) "Continuous Operation Of The Berty Reactor For The Solvent Methanol process" Berty J. M., Tnd. Eng. Chem. Res. 30,1413-1418 (1991)
A method of successively evaluating a catalyst by introducing a synthesis gas under a state of fully filling the Berty reactor with a solvent is disclosed.
(2) Spinning Basket Reactor
1) Myers, E. C. et al.; A. C. S. Sympo. No. 65 37 (1978)
A desulfuration reaction rate of dibenzothiophene contained in white oil is measured by using a Multi Phase spinning Basket Reactor (a name in the reference). Further, a method of performing an experiment is explained relatively in detail.
2) Ammus, J. M. et al; I. E. C. Res. 26, 494-501 (1987)
A desulfuration reaction rate of atomospheric residual oil is measured by using a spinning Basket Reactor (a name in the reference). Further, a method of performing an experiment is explained relatively in detail.
Since a liquid surface within a spinning basket reactor is not largely changed, it is considered that a successive evaluation experiment on a catalyst of three phases of gas, liquid and solid by means of the reactor can be easily performed.
(3) Other Internal Recycle Reactors of Fixed Catalyst Type
1) Jankowski, H. et al.; Chem. Techn. (Berlin) 30, 9, 441-446 (1978)
Various kinds of internal recycle reactors (Gradientless Laboreactor) published at this point of time are introduced.
2) Brown, C. E. et al.; A. I. Ch. E. J. 16 (5). 817-822 (1970)
A reaction rate of gas phase methanol synthesis is obtained by a self-made internal recycle reactor.
(4) Autoclave
As a technique similar to the internal recycle reactor, a method of evaluating a solid catalyst in a gas phase or a liquid phase by using an autoclave has been known by those skilled in the art for a long time.
However, in the Berty reactor mentioned in the above item (1), the reactor mentioned in the item 1) treats only a gas phase reaction system. Further, the method described in the item 2) has the following disadvantages.
(a) A solvent in a liquid phase is not successively discharged.
(b) Since the reactor is fully filled with the liquid, an interface area between the gas and the liquid is insufficient so that a mass transfer from the gas phase is liable to become a rate-determining.
(c) Since the reaction gas is introduced from a lower portion of a magnetic agitator, when the gas introduction rate is increased, there is a case that the impeller moves upward so as to come into contact with a catalyst basket, thereby leading to a breakage. The inventors have actually experienced the breakage of the impeller.
(d) Since a gaseous raw material and a solvent are respectively introduced into a reactor from separate inlets, in the event that the solvent is a heavy oil (for example, an atmospheric residual oil), there is a case that a coking is effected during a process of passing through the inlet portion of the reactor, thereby leading to a plugging. The inventors have actually experienced the plugging.
Further, in the Spinning basket reactor mentioned in the above item (2), the reactors described in the items 1) and 2) have the following disadvantages.
(a) Since the fluid is rotated together with the catalyst basket, an actual flow rate of the fluid with respect to the catalyst can not be evaluated.
(b) When the flow rate can not be evaluated, a mass transfer rate between the gas and the liquid or between the liquid and the solid becomes unclear, so that a intrinsic reaction rate can not be obtained.
(c) Since it is significantly difficult to fix a center of the basket when packing the basket with the catalyst, if the basket filled with the catalyst is rotated at a high speed, a bearing supporting a drive shaft is worn during a short period of time, so that it is not suitable for evaluating a catalyst for several months.
(d) In FIG. 3 of the reference "An Improved Gas Recirculation Reactor For Catalystic Studies", Caldwell, L.; Apply. Catal. 8. 199-213 (1983), it is pointed out that the spinning basket type (this is called as Carberry type in the reference) has less performance than the Berty type.
Further, in the other internal recycle reactors of fixed catalyst type mentioned in the above item (3), both of the reactors described in the items 1) and 2) do not disclose the applied reaction system.
Still further, the autoclave mentioned in the above item (4) mostly performs a screening test of the catalyst in a batch operation, so that it is impossible to obtain data having such a high accuracy as in a continuous operation. Further, although there is an example of evaluating by a continuous operation in such a manner as not to change a liquid surface within the reactor in the same manner as the spinning basket, in the case that the catalyst is not fixed, since a diameter of a particle of the catalyst is changed during the reaction, a correctly evaluated result can not be obtained, and also in the case that the catalyst is fixed by using a cage or a net, since a chart for evaluating a rotating speed and a flow rate when the fluid passes through the catalyst layer as in the Berty reactor is not disclosed, the flow rate can not be evaluated as well.
As mentioned above, in all of the conventional evaluating apparatuses, in the case that a fluid to be evaluated is a liquid phase or a gas-liquid phase, since it is difficult to continuously discharge the evaluated fluid, the apparatus is exclusively used for a gas phase reaction system.
However, it has been strongly desired for a long time to enlarge a range of the fluid to be applied to a liquid phase or a gas-liquid phase in various kinds of technical fields in which it is necessary to use a solid catalyst and to perform various kinds of reactions in a liquid phase or a gas-liquid phase for the purpose of tests and researches.
Incidentally, as a method of evaluating a catalyst under a liquid phase and a gas-liquid phase in the Berty reactor, although the following two references disclose an information that an evaluation of a catalyst under a liquid phase and a gas-liquid phase can be performed, in any of these references, a concrete method thereof is not disclosed.
1) Ohta; Idemitsu Technical Report, 34 (4), 397-402 (1991)
2) 3" Catalytic reactors catalogue No.3821 autoclave engineer company